Octodontid-like Echimyidae (Rodentia) : an upper Miocene episode in the radiation of the family

Diego H. Verzi, Maria G. Vucetich and Claudia I. Montalvo

Reigechimys octodontiformis gen. et sp. novo and R. plesiodon sp. novo are described. They represent the frrst record of the family Echimyidae for the Cerro Azul Formation (Huayquerian Age, Late Upper Miocene) at La Pampa Province, central Argentina. Both species have hypsodont cheek teeth with an eight-shaped occlusal design. This dental morphology represents a noticeable case of convergence to octodontids and indicates that these echimyids inhabited open environments.